Method of and means for automati



July 15, 1941. 1 TR||=LETT Y I Re. 21,859 un'ruon 0F AND'MEANS-FORAUTOMATICALLY OPENING Ami mm A cnzcun Original Filed Oct. 21, 195:. v 6snets-sn ei 1 y i5, 19%??? H. A. .TRlPLE'rT Re. 2

METHOD OF AND MEANS FOR AUTOMATICALLY OPENING AND RECLOSING A CIRCUIT 1Original Filed Oct. 21, 1933 SSheets-Sheet 2 Hggh 0a 2305,62?

Jul 15, 1941. H, A TRIPLE" Re. 21,859 v METHOD OF AND MEANS FORAUTOMATICALLY DPENING AND RECLOSING A CIRCUIT 6 Sheets- Sheet 3 OriginalFiled 0&1. 21, 193;

" 6 Sheets-Sheet 4 1-1. A. TRIFLETT OrigigaIFilqd Oct. 21. 1933 v v v vv A 1 7/47,: L! v fiw/flmfillw w m WMWwZ/g g l/ xx 11/ I1 ///1 I I 1July 15, 1941.

METHOD 0f AND MEANS FOR AUTOMATICALLY OPENING AND REGLOSING A CIRCUIT 6Sheets-Sheet 5 Brzfl v ww H. A. TRIPLETT Original Filed 001;. 21, 1953 Fa 6 v I l 5 w M v .97 7 w 0 m w a w ww W Q I d I II/ /I/ll/I/I.//ll/I mm Z 1/. W 7

METHOD OF AND MEANS FOR AUTOMATICALLI OPENING AND RECLOSING A CIRCUIT13,15. Jam:

July 15, 1941.

I 1 /1 y/I 11,///////////////// r Z nZ ew mp 6 Sheets-Sheet 6 H. A.TRIPLETT METHOD OF AND MEANS FOR AUTOMATICALLY OPENING AND RECLOSING ACIRCUIT- Original F iled Oct. 21, 1953 a a g f a k I 1 Um j t T O |J. 9i f E; 1. FF a Z w M Z Z operations on connected circuits, etc.

Reismea July 15, 941

m!) OF AND MEANS FOR AUTOMATI- CALLY OPENING AND "BECDOSING A CIR- CUITHugh A. 'lriplett, Wilmette, IlL, assignor to Schweitzer I; Conrad. Inc,Chi

por ation of Delaware Original Nu; 2,601,744. m July 20, 1937. Serial'No. 694,584, October 21, 1933. Application for reissue December 15,1937, Serial No. 181,142

il'lClaims.

My invention relates to a method of and means for opening a circuitsubject to overload and thereafter automatically reclosing the circuit.

' While the specific embodiment which I shall herein describe andillustrate in compliance with the requirements of the statutes employs afuse as the element for detecting the existence of overload, and theoperation of the device, it is to be understood that this feature isincidental to the preferred embodiment, and not necesary for allembodiments of this invention. The use of a fuse permits of maximumsimplicity of construction and operation. It provides the best mode nowcontemplated of applying the novel principles embodied in my invention,but I 'do not wish to limit my invention to that mode only.

cage, 11L, a corit has been found that breakers which reclose from threeto five times stay closed upon the first reclosure in probably 80% ofall cases. of f operation. Also, it has been found that circuit breakerswhich are arranged to close twice after. the first interruptionwillreestablish service in about 90% of all cases, and will thereby maintaincontinuity of service.

Such circuit breakers for this service as have been developed areexpensive in first cost. They involve complicated mechanism.

fluene'es which render the devices unreliable. As

In the of electrical power, continuity of service has become a greatfactor. Service interruptions on power transmision or distribution linesoccur from various causes and under various conditions. A large majorityof interruptlomtoservice are causedbytheoccurrence of temporary ortransitory overloads.

Fusx, circuit breakers, or such other safetydevicesasareincommon'usearegenerallydesigned to open the circuitpromptly upon the occurrence of overload, to avoid extending the serviceinterruption toward the source of power. They best serve their functionas protective devices in causing interruption of current flow as quicklyas it is possible to determine the existence of current flow in excessof that which it is safeforthelinetocarry.Sincetheyareintendedanddesignedtooperateassoonasthe current has attainedan excessive value, they are not able to diiferentiate between atemporary or transitory overload or short, and a permanent one.

It is found however, that in a large percentage of such interruptions ofservice, or outages, the

cause is only temporary, such, for example, as

wiresswingingtogethenatreelimbwhichinfallingtothegrcundcomesacmsthelineafla'shoverofaninslflatorduetoavoltagesurgeproducedby atmospheric electricity, or switching Hence, if a line is protectedby a. device without reclosing overload, even if self-clearing incharacter, and when thetrouhlemancomesonthejobtoreestablish service hefinds that the trouble has cleared itself aml no longer exists.

Automatic reclosing oil circuit breakers have been provided for meetingthese conditions and characteristics, the service is interrupted by anya result, their application and use is greatly Also, all such reclosingfuse devices of which I have information have their contacts broughttogether inthe open, or in air, with the result that the contacts tendto burn and sometimes weld together. Also, the rapid engagement in airof contacts carrying heavy current is likely to cause vibration orbouncing,with resultant arcing, pitting. and injury to the contactsurfaces.

In oil circuit breakers of the reclosing type, more or less elaborateoverload detecting device are employed. These are generally of theelectromagnetic type. In a fuse device the fuse itself serves as theoverload sensitive device. Where fuses are employed it is necessary toshift the connections from one fuse to the next, and to do this reliablyand simply has heretofore not been found possible.

According to the present invention I provide-a simple and reliablereclosing device for the service above described. 7

' In the preferred form it employs a fuse as the sensitive element fordetecting overload and tripping the moving parts or initiating theopening of the circuit. The fuse also initiates the operation ofswitching the circuit to the succeeding fuse.

According to one phase of ,myinvention the opening on overload andsubsequent reclosing of the circuit is accomplished by the motion of apart which first interrupts current flow and continues in ite travel,subject to an intermediate time delay, to perform a switchingorieclosing operation, bringing into circuit another or alternativedevice. The primary duty of the device is to open the line upon theoccurrence of overload. The secondary duty is to reclose the line aftera predetermined interval, through a second protective or interruptingdevice.

An important feature of novelty of my invention is the utilization of asingle shiftable member in the dual capacity of opening the circuit atone point and subsequently reclosing it at another point. In the formsherein shown this shiftable member is in the form of a rod which leavesone terminal to break the circuit and travels endwise away from said oneterminal toward a second terminal to close the second circuit.

A further feature of novelty resides in the provision of a timingelement for governing the delay between the operation of circuitinterruption and the operation of circuit closing through anotherbranch. In the preferred form of the invention this is secured by theprovision of a dashpot and lost motion connection of the rod or movablemember relative thereto. Obviously any other timing device, such as amechanical escapement, may be utilized.

A further feature of novelty resides in the enclosure of the operatingparts which interrupt the circuit and reclose it within a housing. Thishousing may be an elongated tubular housing convenient to manufactureand use. Preferably it consists of a cylindrical shell of insulationbearing external terminals such as caps or ferrules. This permits ofconvenience in installation and permits of a simple, inexpensivemounting,

Further features of novelty reside in the spe-. cific construction andarrangement of certain of c the operating parts, namely:-

First, the use of an intermediate terminal of ring-like form, whichprovides connection through the operation of the contained shiftableelement with either the upper ferrule for the initial current, or thelower ferrule for the reclosure;

Second, the use of a coil spring and a concentric rod or tube to producethe necessary travel and toprovide a compact and efficient structure;

Third, the construction of the timing or dashpot mechanism for checkingthe motion of the shiftable member through a part of its travel in orderto provide a time interval between interruption' of the circuit andreclosing;

Fourth; accelerated motion of the movable contact on' closing thecontacts allows them to close together rapidly. thereby reducing thetime during which an arc could jump across the approaching contacts. Inthe present structure these contacts approach each other under shortcircuit conditions;

Fifth, utilizing the same fluid dielectric for arc extinguishing andforthe working medium of the dashpot; (when an arc extinguishing liquid isemployed, it serves the additional function of preventing arcing at thereclosing contacts);

Sixth, the construction of the reclosing contact and particularly theguide to prevent bouncing or chatter of thereclosing contacts;

Seventh, provision of means for permitting dis placement of liquid outof the reclosing part of the device and for escape of gases from saidpart.

There are other features of novelty which will appear from the followingdetailed description and the drawings hereto attached, and forming apart of this specification.

In the operation of the device, the following actions take place:

First, there is the detection of excessive current iiow. When a fuse isemployed this is accomplished by softening or meltingof the fuse.

is accomplished by checking the motion of the movable electrode as bycausing the dashpot to become effective. I

Sixth, closing the reclosing switch, This is done by discontinuing thedashpot action and plunging the movable electrode into engagement withthe reclosing electrode or contact.

These actions may be accomplished by means structurally different fromthe means herein shown, as I do not wish to limit the invention tospecific details except as they are important to the attainment of thefunctions involved, and then only as recited in the appended claims.

The number of reclosures may be varied, and the mechanical position ofthe reclosing units may be varied within my invention.

Now, in order to acquaint those skilled in the art with the manner ofconstructing and operating a device embodying my invention, I shalldescribe in connection with the drawings a specific embodiment of thesame,

In the drawings:

Figure 1 is a front elevational view of an embodiment of my invention;

Figure 2 is a side elevational view of the same;

Figure 3 is a bottom plan elevational view taken from the bottom ofFigure 1;

Figure 4 is a diagram of connections of the device conditioned forfusing the first fusible link. This diagram shows the device in initialcondition;

Figure 5 is a diagram showing the connections after the first link hasblown, and the second link has been switched into circuit;

Figure 6 is a similar diagram showing the connections after the secondlink has been blown and the third link has been connected into thecircuit;

Figure 7 is a diagram of a modified arrangement embodying my invention;I

Figure 7A is a similar diagram of a further modification;

Figure 8, in three parts, is a longitudinal section through the unitfuse and switch of my invention. Part I shows the fusible link and itsconnections for opening the circuit. Part II shows the shiftable contactof the switchelement Figure 12 is a similar cross section, taken on theline lI--l2 of Figure 8, part III;

Figure 13, in three parts, shows, in vertical section, an air expulsionfuse constituting a modification of the unit fuse and switch of myinvention. Part I shows the stationary switch con tact. Part II showsthe movable switch contact nection to the movable terminal andthestation- V ary terminal.

Figure 14 is a longitudinal section through the air expulsion fusiblelink shown in Figure 13;

Figure 15 in two parts shows a further modification of an air expulsiontype of fuse and switch unit embodying my invention. The upper switchcontact is not shown, but it will be understood that it is like theswitch contact of Figure 13, part I; and

Figures 16, 1'7 and 18 are front and side elevations and a top planview, respectively, of a spring clip or contact for mounting the units.

Referring first to the installation shown in Figures 1 to 3 and the fuseand switch units shown in Figures 8 to 12, I provide a mechanism isbolted to the end of the horizontal insulator it. The two horizontalinsulators l5 and I5 are mounted upon the cap of the petticoat insulator26. The connection is made by rectangular bracket member 21 which has ahorizontal portion in the plane of the parts ll, 2| and 5 in order tosupport the swing clip contact 23 for making connection with the lowerferrule of the fuse unit 3. This bracket member 21 likewise has tworight-angle portions which are bolted to the ends of the insulators I5and I5 and it has a bottom portion which is bolted to the cap 25 of theinsulator 26. The lowermost insulator 29 has a cap 30 upon which issupported a bracket of flat stock. This bracket 32 has a portion 33lying in the .plane of the parts 2|, [9 and 5, and it supports thespring clip 34 for making connection with the lower ferrule 35 of theunit 2. The

the purpose of which is to interrupt the circuit automatically upona.rise of current to a value in excess of a predetermined amount,thereafter, after a predetermined period of time, closing the circuitthrough another protective device, which will remain closed if, in themeanwhile, current flow has been reduced, but which, if current'flow isstill excessive, will automatically interrupt the circuit, and, after apredetermined period, connect in a third safety device to close thecircuit which is capable of interruptingthe circuit if the current flowis still above a predetermined value; The same principle of operationmay be embodied in any desired number of reclosures.

The three protective devices l,-2 and 3 are preferably, but notnecessarily, fuse devices. In

the specific embodiment shown, these units are all completely enclosedand the switching is done internally. Units l and 2 are fuse and switchunits, and are identical. Unit 3 is a fuse unit only, hence, in thespecific embodiment, it is the last protective device to be included inthe circuit. Obviously, within my invention, any number of safetydevices may be employed.-

The incoming line connection is made at l to a transverse bus bar 5which is supported upon the cap 5 of insulator-I by a pair of divergentarms, one of which is shown at 3, and a central .arm 51 The two arms Iand the centa'al'arm or bracket 9 space the bus bar 5 away frominsulator cap 6 to bring the fuse clips l2, "and in alignment with otherfuse clips later to be described, allowing room for the transverseinsulators l5, I5 and I'|-. The outgoing, or load connection i8 ismadeto a flat conductor of L-shape, the body of which, indicated at ll,lies in the same plane as theincoming line bus 15. The circuit may runeither way, i. e., either in at 5 and out at It, or vice versa. The baseor right angle portion of conductor l3 extends downwardly in Figure 1,that is, normal to the plane of the paper,'and is bolted to the lefthandend of the horizontal insulator l5. A special clip or spring contact 23is mounted on the body portion .l!

and it receives and makes contact with the metallic ferrule 22 of theunit I. The unit 2- has a similar intermediate ferrule 22 and it also isengaged by a special clip or spring contact 23;

base of the bracket member 32 is indicated at 36. It is bolted to thecap 31] of insulator 29.

A right angle mounting portion 31 extending upwardly from the plane ofthe paper in Figure 1 is bolted to the right-hand end of the horizontalinsulator ll in order to support the same. At its left-hand end theinsulator i1 supports'a bracket comprisingthe horizontal portion 38which lies in the plane of the parts I! and 5 and a foot portion 39which is bolted to the left-hand end of the insulator ll. The horizontalportion 38 supports the spring clip ill for making contact with thelowermost ferrule 35 of the unit I. The clips are thus arranged in truealigned groups for the three units I, 2 and 3.

The three insulators I, 25 and 29 have their pins bolted to a supportwhich, in this case, is a piece of channel iron 45, ll".

The units l, 2 and 3 havetheir upper ferrules l2 (and these aresubstantially all alike), connected by their respective spring clips orcontacts i2, I 4 and I 3, to the incoming line connection bus 5. Theintermediate ferrule 22- of the unit I is connected by its springcontact member 20 to the outgoing line connection or load connectionIll. The lowermost ferrule 35 of' the unit I is connected, to theintermediate ferrule 22 of unit2 by a conductor 43 the ends of which aresecured, as by screws or bolts, to the bracket portions 24 and 38. Thelowermost ferrule 35 of the unit 2 is connected to the lowermost ferruleof the fuse unit 3 by a conductor II- which is bolted to the bottom 35of the bracket 32 and to the bottom of the bracket 21. 'Ashort-circuiting switch II has its contacts mounted on the of thisswitch is to connect line terminals 4 and V II together for closing theline to the exclusion of the units 1, 2 and 3; This is particularlyuseful on re-fusing the device.

The connections are indicated in diagram in Figures 4, 5 and 6.

' Units I and 2 each comprise a fusible link 45 and'a normally openswitch 41. The unit 3 comprises a fusible link 45 but has nocorresponding switch. When the device is initially installed the unitsI, 2 and 3 are connected in place and the I short-circuiting switch IIis open. The switch III is closed only when units l or 2 or both are tobe replaced, in order to prevent interruption of the service as theremoval of an operated unit would otherwise break the circuit. Upon the00-. currence of overload conditions necessitating opening of thecircuit for protection of connected apparatus the fusible link 46 of theunit I is fused and the arc is extinguished, as will be described later.The common moving terminal of the fuse and switch'begins to descend assoon as the fuse is melted and opens the arc gap of the fuse quickly,then it is delayed in its motion and finally, after a predeterminedperiod which is suitable to ascertain whether or not the line willclear. itself,

- and preferably of such short duration as not seriously to interferewith connected rotating machinery, particularly of the sensitive type,the switch contacts 41 of the unit I are closed. This, through theconnection 43, then switches the fusible link 46 of the element 2 intothe circuit and the connections are then as shown in Fig. 5. If theoverload persists, necessitating further disconnection, the fuse 46blows, the-common moving terminal quickly widens the gap, and the are isextinguished. Thereafter, with an intervening period of time, the switchcontacts 41 are quickly closed and through the connection 44 the fusiblelink 46 of the unit 3 is connected in series in the line. Theconnections are then as indicated in Figure 6. If the overload stillpersists the fuse 46 blows and the gap is widened, the arc isextinguished, and the circuit .then remains open.

The spring clips such as I2, ll and I4 are preff erably of the typedisclosed in Conrad Patent No. 1,743,322.; The insulator caps such as 6,26 and III are preferably, but not necessarily, of the type shown in thepatentto Ramsey, No. 1,767,-

398. The fusible links are preferably of the type which are opened byspring action, and provided with are extinguishing medium in the generalmanner known in the trade in connection with the S 8: C liquid quenchedfuse, although they may be of the type disclosed in the patent toRingwald, No. 1,652,317, involving a solid are extinguishing material,or it may be of the air expulsion type shown in the copendingapplication of Allan Ramsey, Ser. No. 671,660, flied May 18, 1933, nowPatent No. 2,091,453. Byreference to the above particular devices I donot intend to limit the disclosure merely referring to the above assuitable structures adaptable to the present use.

. In order that the operation of the units I and 2 may be more readilycomprehended, and that the structure thereof may be clear, I have shownin Figs. 8 to 12 the details of construction of a specific embodimentsuitable for use in the installation of Figs. 1, 2 and 3. The unit 3 ispreferably a fuse of the above mentioned type or, more specifically, itmay be constructed as shown in the copending application of Conrad, Ser.'No.

470,416, filed July 24, 1930, now Patent No. 2,091,430. The unit Icomprises an upper ferrule 41, an intermediate ferrule 22, and a bottomor Between the ferrules 42 lowermost ferrule 36. and 22 extends a glasssleeve 66 which is seated in counterbores in the ferrules 42 and 22 andcemented therein to provide a fluid-tight joint, mechanically rigid.Between the ferrule 22 and the lower ferrule 36 extends a glass sleeve62 which likewise is seated in counterbores in the said ferrules andrigidly cemented thereinto.

The fusible link portion generally designated by the reference numeral46 in the diagram of connections of Figs. 4, 5 and/6, includes detailsof construction which are substantially identical, as herein shown, withthe structure disclosed in the above copending Conrad application,Serial No. 470,416, now Patent No. 2,091,430. This comprehends, in'general, the following construction: A silver fuse wire 63 isconnectedbetween the round brass metal studs 64 and 66, the formercomprising a stationary terminal, the latter a movable terminal. Thestress produced by the tension spring 66 upon the movable terminal 66 isnot taken upon the silver fuse wire 63 but instead is carried by ahigh-tensile strength, high resistance nickel-iron-chromium wire 61which is provided with loops at its ends extending axially in bores inthe terminals 64 and 66 and cross pins extend through the said loops toanchor the ends of the so,-.called "strain wire 61. The silver fuse wire63 is coiled about the strain wire 61 and has its ends mechanically andelectrically secured to the terminals 64 and 66. The upper terminal 64has a threaded stud 68 which passes through a contact plate 66 and-isheld by a nut 60. .The con- .tact plate 69 has a flange which is slottedto provide spring flngers 62 fitting within a counterbore .63 in theupper ferrule 42. The spring fingers of the flange 62 rest endwiseagainst a shoulder which is formed by inwardly projecting flange 64. Theflange 64 is internally threaded and carries a plate of insulation 66which is generally termed the-barrier plate, this being preferably madeof insulation. The barrier plate is apertured at its center and, inturn, carries a tube of insulation 66 providing an explosion or arcingchamber 61. The upper end of the tube 66 is provided with a short flangewhich flts in a counterbore in the barrier plate 66 and is held in placeby washers 68 held in place by pins 68 having heads overhanging thewashers, the washers in turn overhanging the end of the flange of thetube 66. The lower terminal 66 extends into the lower end of the tube 66and the fuse 63 and its strain wire 61 are contained substantiallywithin thearcing chamber-61. The plate 69 is apertured by a number ofopenings and the chamber which is formed above the arcing chamber isadapted to receive and, under certain conditions, retain the products ofthe arc formed upon melting of the fuse and strain wire. 'This chamberis closed by a releasable vent cap III which is cemented over the end ofthe ferrule 42 with a predetermined yielding value, to retain theproducts of blowing of the fuse if possible and, if not, to release uponthe occurrence of excessive pressure and to vent the explosion chamber61 to atmosphere or to an enclosed space of suitable character.

I up to .the level L shown in part 1 of Figure 8.

The liquid director I2 is carried by a plurality of pins I3 projectedradially outwardly into a groove formed in the interior wall of theliquid director I2. The stud 66 has an integral enlarged shank or bodyportion I4 providing a shoulder. Upon the annular shoulder formed on theshank or body portion I4 rests a flange I6 of the spring anchor I6. Asplit snap ring II is positioned in a suitable groove in the shank I4 toprevent the latter from moving downwardly relative to the spring anchorI6, which movement might be caused by the pressure created on melting ofthe fuse wire 63 and strain wire 61 under heavy overload conditions.This spring anchor is a cylindrical sleeve member having spiral grooveson itsouter surface to receive the upper convolutions of the spring 66.The spring. 66 is threaded by flexible copper braids 11. These braidsare stranded wires which extend endwise through holes drilled in the nutI8 and have their ends pinched between the thread nut II and the lockingnut 19, both of the parts 18 and I! being threaded upon the upperthreaded end II of the rod 82. The nut 18 is threaded against theshoulder formed on the upper endof the rod 82, the flexible conductorsll extend through the nut II and have their ends turned out radially andclamped by the lock nut I which is then pinned against rotation. Theupper end of the threaded stud 80 extends into a threaded socket in theshank ll of the upper terminal 55. The terminal 55 may be a removabletip separable from the shank 14, if desired. The rod 82,-which is a.conductor, preferably a rod of copper or brass,

has its main length of reduced diameter to provide a portion of largerdiameter which may be termed an'enlargement' 83. This enlargement has adistinct purpose which will *be described more in detail later, namely,a guiding function in the lower spring anchorage, and a valve closingfunction in connection with the dashpot.

' The lower end of the tension spring. 58 is connected to a springanchor 84, this spring anchorcomprising a cylindrical portion which, 11111 its exterior periphery, has helical grooves for receiving the lowerconvolutions of the tension ,pressedbetweenthesprlngheadortipfland Q thesaid guiding neck III, a suitable washer "2 spring 56. A central opening85 is provided to 7 permit the passage of the rod 82 therethrough. Thespring anchor 84 is drilled endwise to receive the lower end of theflexible conductors II, the ends of said conductors 11 being turned outradially and clamped against the end oi a threaded ring or plug 86. Thespring anchor 8| has a tubular neck which extends down through the ring86 and said ring 86 is counterbored to receive an internally threadedcollar 81 threaded onto the neck of the spring anchor 84 to hold itfirmly in place and to clamp the ends of the flexible conductors "llbetween said spring anchor 84 and the upper face of the threaded ring orplug 85. The threaded ring or plug 86 is threaded into the upper end ofthe intermediate ferrule 12 to provide good electrical conductivitybetween said flexible conductors ll and the intermediate ferrule 22. Theflexible conductors, in turn, make good electrical connection of'lowresistance with the lower fuse terminal 55 and with the rod 82. Thethreaded ring or plug .88 is slotted to provide a plurality oflongitudinally extending ports 88 so that communication is providedbetween the chamber 88 formed above the intermediate ferrule 22 andchamber 88 formed below the intermediate ferrule 22. The lower end ofthe rod 82 carries a switch contact 82 which is threaded upon the rod.This contact 92 is'adapted to plunge into and'make engagement with thestationary switch contact 88 secured in a boss ll on the interior of thelower ferrule 85 which has an end wall closing the same. In other wordsthe ferrule 35 is in reality a closed cap. a

In the intermediate ferrule 22 below the upper threaded portion whichreceives the ring or plug through the use of the sleeve 95. The head 81has a plurality of ports therethrough, one of .which is shown at 98. Aflat disc valve 88 cooperates with the port 98. This disc valve 9! therod 82. The valve is held in raised position being interpom between theupper end of the 7 spring and said guiding neck. The disc isheldseparation from the plunger by a pair of headed pins I83 (see figure 10)which have their lower ends fastened in the head 81 and have theirintermediate portions passed through holes in the disc 89. Itisdesirablethat the valve 88 remain away from the ports 88 so that gas, for exampleair, which may find its way into the lower compartment Il may gravitateout of said compartment "and rise into the upper compartment above theliquid level. As soon as the dashpotistobecalled intoplamthevalveistobeclosed and this is accomplished by the enlargement 83 passing downthrough the central opening 85 in the lower spring anchor 8| andengaging the disc 88 and forcing it against the head 81, closing thepassagewayof openings I8 through said head.

The plunger 85 of the dashpot is guided within the bore in theintermediate ferrule 22 but as soon as the head 81 passes out of saidintermediate ferrule 22 it passes into the largerpart of the chamber 88,which is of an internal diameter substantially in excess of the plunger85, with the result that the dashpot action becomes substantiallyineffective. The action of closing the valve 88 upon the ports 98 andhead is shown in dotted lines in part 8 of Figure 8. The lower switchterminal SI comprises a plurality of spring fingers integral with thestud portion III or contact a as is indicated in dotted lines in Figure8, part I.

I have found it desirable, in closing the switch contacts, to preventstriking and chattering or bouncing of the contacts. since with heavycurrent flowing that is most destructive of thecontactingsurlacesandalsolttendstoevolvegas,

'whkzh, in a device of limited capacity, is unde- "Bakelite", which isheld in place by a groove on the lower outer periphery by hooks orinwardly extending portions formed on the upsirable. "I provide aguiding ring I ob suitable insulation, such as "BakeIiI-ed fiber, or

perendsofthesprlngfingersofwhichthecontactlliscomposed. Thesleeveiofthedashpot encircles the lower contact, as shown in dotted lines inpart I of'Figure 8, only after the contacts are closed and the saiddashpo't drops down through the liquid. The insulating guide ring II isfunnelrshaped to guide the movable contactflinplace.Itisnotaorexpandingring butasolid ring,andisheldinplacemerelybythegripofthehooksontheupperends of the springfingers under theinfluence of the oollspring lllwhichis ahelicalspringwiththe endsthereof hooked together and I has a guiding neck ill to guide the valveupon thespringfingersofthecontactll (seelllgure 12). Obviously theconstruction of the guide ringmaybemodiiledasbydividingitorevm providingseparate extensions on the finger-so! the contact 83.havesuchaguideofinsulationforbringingtwo normally by a coiled spring inwhich n coin- Ibelieveitisbroadlynewto' 6 v switch contacts together forclosing a circuit under heavy load. The contacts are notseparated underload, hence the guide is never burned.

The operation of the unit shown in Figure -8 and the manner in whichthat operation afl'ects the operation of the installation shown inFigures l to 3 will now be explained.

The entire unit is filled with liquid up to approximately the level Lshown in Figure 8, part I. This level may be slightly higher or lowerwithout aifecting the operation of the device. It is preferable that theliquid be kept out of contact with the fusible link both in order toavoid any influence upon the time-current characteristics, and also tokeep the heat of the fuse away from the liquid. Assume that the partsare as shown in solid lines in Figures 1 and 8, current from the linelead 4 passes through the line bus 5, through the spring clip l2 and tothe ferrule 42. From here the conduction of current is the stud or upperlink terminal 5|. From thence current flows through the fuse wire 53 andin small degree through the strain wire 51 to the lower terminal orarcing tip 55, which is connected through the shank or body 14 and rod80 and nuts I! and 18 to the flexible cables 11. From thence currentflows down to the lower spring, anchor 84, in which the lower ends ofthe flexible cables 11 are connected, to the ring or plug 85 and thenceto the intermediate ferensue through the spring fingers 52, the plate59, to

rule 22. At this time the fact that the rod 82 and the switch tip 92 arelive, that is, connected to the circuit, is of no consequence since therod is out of contact with the guide formed by the lower spring anchor84 and the tip is in contact only with'themovable plunger of thedashpot. this movable plunger '95 being of insulation and hence nocurrent flows through the rod 82 at thistime, Obviously, the rod 82might make connection between the arcing terminal and the intermediateferrule 22, but that is of no consequence since the flexible cable 11 isof very low resistance in order to put the said parts 55 and 22 in goodelectrical connection.

Assuming that the short-circuiting switch III is open, all of thecurrent flow between the terminals 4 and I8 passes through the fuseele-- ment, including the link 53 and its strain wire 51. If an overloadoccurs, and this may be :either a short circuit in which a very largecurrent flow immediately develops or it may be a fault of a character inwhich the current flow is limited, the fusible link is melted, releasingthe terminal 55. As soon as the fuse is melted it is,

of course, pulled apart and thearc which follows times and instantlyupon the formation of an are some of thismaterial is vaporized and the'metallic vapors and the arc extinguishing mediwithin the device to apoint where the cap 10 is blown oil, providing for release of pressureto atmosphere or to an enclosed space of a suitable character. Theinjection of liquid by descent of the plunger, including the liquiddirector I2, in-

creases the length of the arc gap and continues to scour out theproducts of the arc, substituting fresh arc extinguishing medium for theproducts of the arc, with the result that in a short travel of the lowerterminal the arc is extinguished. This downward travel of the plunger,including the rod 82 is accomplished with relatively rapid motion. Thisbrings the enlarged portion 83 down into the guide opening 85 in thelower spring anchor 8'4 and then causes the said enlargement 83 toengage the valve disc 99 to close the same over the valve ports 98. Thismakes the dashpot effective to retard the downward motion of the plungertowards switch closing position. The length of time that the dashpotpiston 95 travels in its cylinder and the degree of clearance .betweenthe piston and the cylinder, may be so to limit the time intervals tosuch short periods,

for the delay maybe a matter of three, four or five seconds, or a timeof that order. It is, however, highly desirable that this time period hedefinite and uniform after it is once determined.

-When the lower contact 93 is engaged by the plunger contact 92 thecircuit is then closed from the line connection l, line bus 5, springclip 14 of unit 2, through the unit to the intermediate ferrule 22 ofunit 2, thence through the external conductor 43 to the lower ferrule 35of unit I and through the closed switch contact 93 and 92 up through therod 82 'to the upper end of the rod, flexible conductors 11 and thenceto the intermediate contact 22 which is connected to the load terminall8. Unit 2 operates in the same manner as unit I upon the flow of excesscurrent therethrough. That is to say, if the fault has not cleareditself, then unit 2 operates through fus-.

ing of its fusible link, rapid descent of the plunger to lengthen andextinguish the are, then a delayed descent through the action of thedashpot, then finally a rapid closing together of the contacts when thedashpot becomes ineffective and thereby switching in unit 3. Unit 3 isafuse only, inasmuch as it requires no switching operaum thus evolved,or evolved by injected liquid,

drives the products of the are into the upper chamber above the arcingchamber 51, where they are removed from possible influence upon theconductivity between the terminals 54 and 55. If the-overload is notsevere this action of endwise expulsion of the products of the arc maysuflice for interrupting current flow. If not, the continued injectionof liquid and the action of the are upon the same may increase thepressure tion for a succeeding unit, hence its operating parts aremerely like'the upper parts of units I and 2 in that it contains thefusible link, ter minals and spring, together with the arc extinguishingliquid or other medium for insuring extinguishment of the arc.

It is to be observed that the descentof the plunger in the liquidperforms a highly desirable function of disconnecting and separating andlnterposing a dielectric medium between the fuse terminals, so thatthere is no possibility of establishing either normal current flow orleakage through the blown fuse.

The dashpot provides an accurate timing device. Where timing is reliedupon as to reclose within a definite interval less than that requiredfor other protective devices such as low voltage trips or controllersfor rotating apparatus-on the line, it is highly important that theinterval be accurately determinable. and that it be not greatly varied.-I have found a dashpot to be preferable to all methods with which I amfamiliar, out obviously I do not wish to limit the timing device to thisspecific device, as any equivalent device, such as a reciprocating orpendulum escapement, or rotary brake, or the like, which will givesatisfactory delay to the reclosing operation, is considered as comingwithin my invention.

Within my invention. sumcient delay may be secured without any specifictiming device. Sequence of the two operations, i. e., interruption andreclosing, is essential. The special timing device is optional.

It is not desirable to use solder in making electrical connections in adevice of this type. This is particularly true where the parts areadapted to be retained in the circuit after the fuse has blown. I

Whereas the fusible link and its arcing chamber, as shown in Figure 8,are for relativelyheavy current, it is to be understood that for lightercurrent a form of fusible element and Patent 1,743,322 or Ramsey Patent1,907,581 may be employed.

;rule member 22, which is made of metal, provides the dashpot cylinder.The construction so provided is particularly advantageous where glasssleeves are employed,'and in this connectionattention is called to thefact that the lower end of the intermediate ferrule 22 is provided withan annular groove into which the upper end of the glass sleeve 52projects and is cemented, a suitable cement for this purpose being ametal alloy as disclosed in the patent to Conrad, No.- 1,665,-

While in the foregoing'form of the fuse switch unit the dashpot isformed in the intermediate ferrule, it is to be understood that this isnot essential in all forms of my invention but it is particularly usefulfor the liquid quenched type. In the air-filled unit shown in Figure 13,the wall of the chamber itself may form the dashpot cylinder. Also, as'Ishall show in Figure 15, a separate cylinder for the dashpot may beprovided and inserted within the device.

In the embodiment of F'Igure 13 the fuse is ofthe so-called expulsiontype; that is, it is blown and extinguished in air. In this embodimentthe fuse is preferably placed at the lower end of the unit, the fusiblelink being indicated at I, Figthe insulating sleeve tube m which forms ahousing or container for the expulsion fuse. The

bore of the tube I58 is made relatively small, so

that a violent expulsion action is secured for throwing out the lowerend-of the fusible link and its connected terminal. The sleeve I" ispreferably formed of a material such as Bakelized" fiber or horn fiberor the like, and it is preferably lined with a fiber or paper liner I51which may be impregnated with an arc extinguishing material which, underthe action of the arc, yields a gaseous arc extinguishing mediumassisting in putting out the arc and interrupting the current flow. Atits upper end the tube I56 is provided with a threaded split metallicring II! which is set in a groove and pinned to the upper end of thesaid sleeve I56 for threading the upper end of the sleeve into themetallic ferrule or ringliB. Threads formed upon a fiber tube, are notgenerally satisfactory, particularly under 'heavy stress or when thethreads are to be released and again tightened and a metal insert laidin a groove in the upper end of the tube I56 is in this case provided.The ring or ferrule I59 I connections such as shown in Figure 1 ofConrad is preferably made of brass or other high conductive metal. Ithas an annular recess cut axially into the upper side to provide first athreaded wall I" for receiving the threads on the lower end of the tubeI 62. A metal insert for the end of the tube I82 may be formed,although, in the case of the larger size tube a fairly coarse threadwill be sumcient, inasmuch as no great mechanical stress is imposed uponthese threads. Drill holes extending axially in the central boss I6!provide sockets for receiving the lower ends of the flexible strandedleads 11. These leads are secured by pinching the metal walls of theholes I upon the ends of the flexible'leads. The annular recess alsoprovides a seat for the lower end of the compression spring Iii. Thecoiled compression spring I65 bears at its upper end against the bottomof the piston I. This piston com prises a main cylindrical body portionI51 which is adapted to fit closely within the tubular bore of thesleeve I62 to form a dashpot providing the delayed motion of the movableplunger. This body portion I61 may he made of a suitable materialsuchfor example as Bakelite, or it may be made of graphite to reducefriction with the walls of the cylinder. The body portion In surrounds aflanged metalsleeve member I". The flange I69 bears against the upperend face ure 13, part III. The fuse has an upper terminal comprising, acylindrical fitting 5 which has a threaded stud I at its upper endadapted to thread into the inside of the lower end of a tube of copperor other good conductive metal, as

shown at I". This tube constitutes an essential of the plunger elementwhich serves the dual function of opening the arc gap and closing theswitch in predetermined order and subject to a suitable time delay.

The lower end of the fusible link I comprises a terminal I which has asocket I" swaged upon or otherwise connected to a flexible cable ISI.This cable I! hasa tapered conical ferrule I52 swaged or otherwisesecured thereupon, and it fits into a conical socket or seat formed atI53 on the lower end of a bracket lil extending from the ferrule I55.The ferrule I5! is seated upon of the body portion I61 of the piston anda flanged not I" is threaded upon the lower end of the said sleeve I68and bears against the lower end face of the body I81. The upper end ofthe spring I 55 bears against the flange of the nut I10 and tends tothrust the piston and the entire plunger member upwardly. A tubularcontact member I12 which forms a part of the reclosing switch, isthreaded into the upper end of the sleeve member I" and makes electricalcontact therewith. The extreme outer end of the contact member I12 isrounded or tapered to assist it in being guided into contact with thesta tionary' contact member I13 which is mounted at the upper end of thesleeve I52 electrically in connection with the ferrule I14. The ferruleI14 is closed at its upper end, constituting a cap, and this cap isthreaded upon the upper threaded end of the fiber sleeve I82.

The flanged nut I10 is drilled axially to receive the upper ends of theflexible leads 11, the walls of the opening being collapsed upon theends of the cables to make electrical and mechanical connectiontherewith. The upper end of the plunger rod I41 is flanged at I15 and isloosely held within the nut I10, this nut being drilled and counterboredto receive the tube I41 and to retain the flange I15.

Whereas the body I61 of the piston is fitted closely to the 'inner wallsof the tube I62, it is v 7 not desirable to retard the operation of themovthegrooves I18 provide a by-passing action forthe piston I66 so thatthe movement of the plunger is rapid in bringing the switch contactsI12I13 into engagement.

Inasmuch as it is desirable to provide for re-- fusing of the units inthe field and this involves pulling the piston down against the spring,as

' will' be explained later, I provide a check valve to permit the pistonto the drawn through the cylinder I11 without the necessity forovercoming the suction which would be created by such movement of thepiston in the cylinder portion I11. To this end a valve body I19,fitting loosely within the flanged sleeve I68 of the piston I66, isprovided. This valve body is tubular in form and has a flange I82 whichis clamped against the lower end of the sleeve I68 by the shoulder I80within the nut I10 and a small spacing ring I83. The valve body I19 thusmakes a fluidtight joint with the sleeve I68. At the same time, thespacing ring I83 provides for a degree of freedom of the connectionbetween the nut I10 and the flanged upper end of the plunger tube I41.The valve, body I19 has a bore therethrough, this bore I84 communicatingwith the bore I84 of the valve body I19 to the spring chamber, that is,the space below the piston I66. The valve body I19 has a counterboreterminating in a conical valve seat I86. A conical valve I81 is guidedin the counterbore and is held against displacement by a guard I88formed integral with the lower end of the switch contact I12. The valveI81 has a bore therethrough in which is seated an adjustable vent, thisadjustable vent being in the form of a screw I89 having a. graduatedpassage drilled therethrough to provide for the escape of air from thedashpot at a predetermined rate.

The valve is intended to operate as a check valve with a controlledby-pass or vent consisting of the passageway I90 through the machinescrew I89.

In operation the parts are first set in the condition shown in Figure13, that is, with the fusible link I44 in place and the terminal leadI50 making contact with the lower ferrule I55 through the brackets I54.A mounting, such as is shown in Figures 1, 2 and 3 may be provided, thespring contacts being modified accordingly, and the element 3 being 'afuse of the type disclosed herein or as shown in Conrad Patent No.1,818,382, or as shown'in the copending application of Allan RamseySerial No. 871,660, filed May 18, 1933. The mounting as shown in Fig. 1may be employed by turning it upside down to arcing terminals I92 andI93 which aresubstan tially identical in construction. These arcingterminals have flanges I94 and are threadedas at I 95to receiveconnecting studs I96 from the upper coupling I45 and I91 from the lowercoupling I48. Coupling I48 has a socket receiving the upper end of theflexible leads I50, this socket being swaged upon the end of thefiexibleleads or otherwise secured thereto. The arcing terminals I92 and I93comprise cylindrical portions which are drilled axially to receive thestrain wire I99 in the center and are drilled to receive the silver orother metallic fuse wire 200. A sleeve of glass or insulation ofsuitable .character 202 surrounds the strain wire I99.

The fuse wire 200 has its ends projected into the endwise drilling inthe arcing terminals I92 and I93 and the body thereof coiled about thesleeve of insulation 202. I

The ends of the strain wire and the ends of the fuse wire are pinched bycollapsing the walls of the holes in which they project to provide agood mechanical and electrical bond. A suit the insulating sleeve 203 asplit cylinder of cork 205 is seated, this cylinder of cork being heldin place between the flanges I94 of the arcing terminals and closelygripping the said arcing terminals and the sleeve 203 by meansv of awrap-' ping of paper 206 or the like. In the preferred form of thedevice, the cork 205 and its wrapper are omitted. The fusible link I 44may be of any suitable design.

With the parts in the position as shown in Figwe 13 and the unitconnected in an inverted mounting of the type shown in Figures 1, 2 and3, the operation is as follows: Assume that the unit shown in Figurel3is unit I, of Figure 1,

Upon the occurrence of overload the fusible link I44 melts, releasingthe plunger rod I41. At the spring I65 expands, driving the piston andplunger rod upwardly with a rapid motion, ex-

tending the length of the arc and assisting in the extinguishing of thesame. The removable liner I51 may assist in the putting out of the arcand interruption of current flow. The liner I61 may be a sleeve of solidarc extinguishing material either with or without a backing, or it maybe a porous material embodying solid or liquid arc extinguishingmaterial either in the free state or in combination. This liner isOptional.

The rapid separating motion of the arcing terminals proceeds far enoughthat the arc will be extinguished by the time that the piston I86reaches the dashpot cylinder portion I11, where escape of air whichpreviously occurred around the piston through the grooves I16, I16, ispre- Upon thevented. The air which is trapped above the piston when itis in the cylinder portion I11 is permitted to escape slowly through theclearance of the piston with the cylinder walls and through I thedrilled passageway I66 in the valve I61. As

soon as the piston passes beyond the end of the cylinder portion I11 theplunger again moves rapidly because of the by-passing eflect of thegrooves I16--I16 around the piston I66 and the movable contact I12 isthen plunged into engagement with the stationary switch contact I16, the

insulating guide ring I66 serving the same functhe sleeve I56 is movedclear of the lower end of the plunger tube I41. The arcing tip I45 isthen unscrewed from the tube I41 and a new unit put in place.The'iiexible lead I56 beyond the plug or button I52 is long enough toextend completely through the tube I56 when it is screwed back intoplace. The projecting end of the flexible lead I56 is then grasped andthe plunger and its connected parts pulled downwardly until the buttonI52 is brought into a split socket or seat I56 and I the end of the leadI56 is then cut-01f and the device is again ready for operation. Whenthe movable piston is thus pulled downwardly, the

- piston I66 is prevented from creating a reverse dashpot action by theaction of the valve I61 which is automatically raised from its seat,providing a free passageway from the spring chamber into the space abovethe piston I66.

In the embodiment shown in Figure 15 the method of securing a dashpotaction differs from that shown in Figure 13 but the general mode ofoperation is substantially the same. In this construction a metalliccylinder for the dashpot piston is provided. The upper sleeve ofinsulation I62 supports a cap I14 as shown in Figure 13, part 1, with asuitable switch contact I13 and guiding ring I66, these parts beingomitted for the sake of clearness. The lower expulsion tube I56 and itslower ferrule I55 a're substantially the same as in Figure 13. Theplunger rod 266 is coupled tothe coupling I45 of the fusible link I44,as shown in Figure 15, part 2; andat the upper end of Figure 14.. Thefusible lihk'I44 is otherwise identical with the construction shown inFigure 13 and as illustrated in detail in"Figure 14. The plunger rod 266extends through the intermediate ferrule or terminal I56 and hasconnected along its intermediate part the flexible leads 11, the lowerends of which extend through drill holes in the boss I64 and are clampedin a counter-bore in the lower side of the intermediate terminal I56, asby means of the washer. 261 which is engaged by the upper end of themetal lic fitting 266 secured upon the upper end of the expulsion fusetube I56. Obviously, the washer 261 may be held in place by a separatering threaded into the counterbore above the metal fitting 266 of theexpulsion fuse tube. Above the connection of the flexible leads 11 therod 266 extends through the movable dashpot 266 and is threaded into aswitch contact member 2 III. The contact 2I6 has a skirt 2I2' withinwhich is housed a compression spring 2l6.. This spring 2|! tends toexpand to throw the swtich contact from motion by'the fusible link H4and its connected lead I56. The spring 2 I6 reacts against a flange 2 I4carried on the upper end of a tubular piston rod 2 I 5. The tubularpiston rod 2 I 5 is con nected at its lower end to the dashpot piston2I6 which piston M6 is engaged by the upper end of the compression coilspring I65. Thus the force of the spring I65 is exerted through thepiston 2I5, the tubular rod 2I5, flange 2I4, and skirt 2 I2 of the tip2l6 upon the rod 266, which rod is restrained from motion by the fusiblelink. The

, movable cylinder ill of the dashpot has an annular shoulder 2I6 whichmoves in the enlarged portion of the bore of the sleeve I62 and, is

2I6 upwardly. However, the rod 266 is restrained limited by a bufferring 22I at the junction of the enlarged bore of the sleeve I62 and itsnormal or reduced bore. Below the shoulder at the bufier ring 22I thetube is of larger internal diameter than above .said shoulder. Thecylinder 2 I I has a head member 2 I 6 through which may be formed aleakage or vent port 226 to permit the escape of air from inside thecylinder when the piston H6 is moved upwardly in the cylinder and viceversa to control the entry of air when the piston is retracted from thehead. A pair of spring de tents 222 having their outer ends providedwith hooks and provided with an intermediate diagonal portion 226 forunlocking the hooks, constitute means for holding the switch contact 2I6and thereafter releasing the same. These detents 222 are relatively longspring fingers mounted upon the cylinder head 2. The lower end of theskirt 2|2 of the switch contact 2 I6 has a flange which is adapted to becaught by the hooked ends of the detents 222. The diagonal or releaseportions 226 are adapted to be engaged by the flange member 2 when thesame is moved upwardly and the flange spreads the detent so as torelease the switch contact to permit the spring 2 I6 to throw the switchcontact 2I6 suddenly into engagement with the stationary switch contactsuch as I16 shown in Figure13.

The operation of the device in an installation of the type shown in Fig.l, suitably designed to permit successive fuses to'be introduced intothe circuit, is as follows: Normal flow of current from the incomingline proceeds to the intermediate ferrule I56, from thence through theflexible leads 11 to the plunger rod 266. From'here the current. flow isthrough the fusible link I44, its lead I56, brackets I54 and lowerferrule I55 which is connected to the outgoing line, or load. Uponthe'occurrence of excessive current flow, such as will cause melting ofthe fusible link, the strain wire I66 yields and the arcing tips I62 andI66 are separated with a resultant explosion, or expansion of gases andvapors, expelling the lower terminal and its lead I56 and permittingimmediately both the spring 2I6 immediately beneath the switch contact2I6, and the main spring I65 under the piston of the dashpot, to expand.The upper spring 2I6 is free to expand without any retardation exceptthe inertia of the parts, whereas upward motion of the parts engaged bythe spring I65 is more or less retarded by the fit which the flange 2I6of the dashpot cylinder 2" has with the enlarged bore as well as thebackward thrust of the spring 2 I6.

pressed, is provided.

prevented. The main spring lil,.however, rapidly throws the cy n er'illupwardly until the flange Ill engages the buffer ring Ill, stoppingfurther advance of the dashpot cylinder Ill. The spring detents I22 andthe contact Ill and rod 2 are moved up with cylinder 2" until it isstopped. The motion of the piston ill is then delayed by the entrappingof air between it and the head 2", the air gradually escaping throughthe clearance and through the vent til until the '0f the fuse out of theclips when the bail or flange Ill arrives in contact with the diagonalportions 22! of the spring detents 222. This flange member Ill forcesthe detents apart and releases the switchterminal Ill. By the advance ofthe flange member 2 toward the diagonal contact Ill into engagement withthe stationary contact I13, thereby closing the circuit to the nextunit. I

In re-fusing in the fleld the operation is as previously described inconnection with Figure 13.

The expulsion tube I56 is unscrewed, exposing 9,5

the lower end of the rod III. A fusible link, with attached flexibleterminal I" of a length suitable to extend out of the lower end of thetube I" before the springs ill and ii! are complaced and the terminal I"pulled downwardly, the springs are compressed and the parts move intothe position shown in Figure 15. In order to insure the separation ofthe piston ill from the cylinder head III a suitable stop may Beprofusiblelinkandtheswitchcontactfll,isflrst40 given a rapid movementfor the extinguishment ofthearc. Themotionof the partsisthen arrestedwhile the dashpot is collapsed and then the switch contact is releasedfor a rapid-final movement in closing the contacts to shift the circultto the next unit.

In mounting the units heretofore descrlbed,'or similar units, in anamembly such as is shown in Figures 1, 2 and 3, I employ, for the upperand lower mounting clips, or spring contacts, spring so terrupter' and atransfer switch, all within the "same housing. While! haveshown the fuseas clipsofthecharactershowninthepatentto Conrad No. 1,665,446. Theseclips employ a wire bail folding longitudinally of the fuse over theendsofthefusetospringtogetherthesprlng jaws and also to prevemaccidental displacement out of the spring jaws. Inasmuch as a bailcannot be employed on the intermediate contact, I provide a contact suchas shown in detail in Piguru16, 17 and 18. Inthis constructionthemainJaws are formed of a U-shaped spring member 2" having the sides doubledupon themselves to providethe contacting portions 260-286; Where ,2the'sideofthe ferrule orcontact onthefuseisg slabbed of! to provide flatsides, these contact.

portions "H" are straight. If the ferrule is a cylindrical, then thecontact portions 266 may bccurved to conform to the outer cylindricalsurface of the ferrule.

Thelowerendsofthearmsf abutagalnst reinforcing arms 26] formed of' aU-shaped'70 spring member. of the members ill and l" are clampedtogether upon a sun-- portingbarsuchas llasbymeansofboltssuch as "landthe base I of a bracket Ill. The

When the tube lit is re- 30 cause the end of the ferrule to preventlongitudinal displacement.

Projections 213 are pressed inwardly above the contact portions of thecontact arms I to provide resistance against accidental displacementclamp is released. 'Simflar projections ill-I'll are pressed out of theouter arms of the contact members I" and one of these serves as a detentfor engagement by the hook-shaped end I'll of the clamp or latch memberI'll. This clamp or latch member is channel-shaped in cross-section withthe'rlng or eye I'll mounted upon the back of the channel, and the-sidesof the channel bent down as shown at I'll-I'll in l'igure 16 over theextreme ends of the U-shaped contact member Ill. contour to flt thecylindrical curved end or b ight III of the reflexed arms I", preventsthe end of the latch or clamp I" from dropping downwardly. A cylindricalcollar 28! is disposed within the curved bisht or bend and a trans-,-verse pin extends through the sides of the latch or clamp and throughthe collar, thus providing the pintle of a hinge.

The operation of the device is as follows: When it is desired to inserta fuse the operator unlatches the clamp or latch I'll by inserting ahook in the eye Ill and pulling outwardly. The detent formed bytheprojection 214 resists such outward motion but the nose 215 of the latchrides over the detent and the clamp or latch may then be swung clearofthe contacts for the insertion or removal of a ferrule.

Obvimisly,insteadofusingwirebailsonthe end clips, contacts such as shownin Figures 16 to la may be employed for both the end and theintermediate contacts. or for any other similar mimosa I I do not intendto limit the intermediate contact to the above form, as any suitablearrangement for mounting the units in the assembly may be provided.

It is broadly new. so far as I am aware, to provide a unit whichinvolves a safety circuit inthe safety element it is tobe understoodthat a switch el cally released, as disclosed inthe patent to Conrad No.1,338,069, may be combined with the transfer switch to provide thenecessary safety overload interrupter and the transfer switchfor'transferrlng the current flow to a succeeding unit. Also, instead ofcarrying contacts. which provide not'only the electrical connectim butalso the mechanical support. The complete enclosure of all the operatingparts is desirable,- particularly the cimult interrupting and circuitclosing portions.

An important concept resides in the common movable element whichpartakes of the fuse inpting or openlng'motion and of the switch bracket21. is cut out as indicated by the line. closingmotion.

A transverse web I'll of cylindrical In Figures 7 and 7A I haveindicated diagrammatically variations which my invention may take withinthe broad aspects of the same, namely, in Figure I I have shown a fusewhich me chanically supports a movable member which, at its lower end,provides a bridging contact for closing the transfer switch to include asecond unit. The fuse may be directly in tension.

The combined fuse and switch of Figure 'l is preferably enclosed in acommon housing with external contacts, as indicated by dotted lines inthe diagram of Figure '7. This specific arrange ment does not lenditself so readily to the elongated, small diameter housing.

Likewise, in Figure 7A, I have shown a similar arrangement in which atension member is sup-. ported. by the fuse. The fuse may be directly intension and connected to the switch blade. The fuse, in turn, holds opena swinging switch arm. The switch and fuse unit is contained within asingle enclosure, which may be partitioned into minal, a plunger in thehousing having a movable fuse terminal, a movable switch terminaladapted to be moved by said plunger, a fuse between one end terminal andsaid fuse terminal and holding the plunger against motion. a stationaryswitch contact connected to the other end terminal and being adapted tobe engaged by the movable switch terminal, said movable fuse ter- 'minaland movable switch terminal being con-- chambers, but the melting of thefuse permits the motion of the switch closlng member tooccur.

The piston of the dashpot may be stationary and the cylinder carried bythe plunger.

In the air expulsion units the walls of the spring chamber may beslotted away to permit visual inspection of the device to determinewhether the unit has been operated. Such slots may be covered bytransparent closures or a single glass sleeve. 1

I do not intend to be limited to the details shown and described, butintend to include 'all variations which will occur to those skilled inthe art, and which come within the spirit of my invention.

1. In a device of the class described, a terminal for an incoming lineconductor, a terminal for an outgoing line conductor, a fuse deviceconnected at one end to one of said terminals; an interrupting andreclosing device comprising three stationary contact terminals, thefirst contact terminal being connected to one of said line terminals,the second contact terminal being connected to said other line terminal,and the third contact terminal being connected to the other end ofsaidvfuse device and insulated from said second contact terminal; saidinterrupting and reclosing device including a circuit interrupterbetween said first and second contact terminals. said circuit closer-andcircuit interrupter comprisinga. common movable element for successivelyoperating the circuit inte'rrupter to open the connection between saidline terminals and then the circuit closer to connect said'fuse devicebetween said line terminals.

2. In a device of the class described, the combination of a firstterminal, a second terminal spaced from the first terminal, and a thirdintermediate terminal, said terminals being supported in insulatedrelation and in alignment, a movable rodlike member normally connectingthe first and third terminals, means for holding said member in circuitclosing position during normal current flow, and means acting uponexcessive current flow to shift said movable member endwise away fromthe first terminal to interrupt current flow between the first and thirdterminal and toward the second terminal to establish a path for currentflow between the third and the second terminal.

3. In adevice of the class described, a housing having end terminals andan intermediate ternected to said intermediate terminal, and a body ofarc extinguishing material adjacent the fuse for providing an arcextinguishing blast, and a spring tending to move said plunger.

4. In a device of the class described,-a plurality of fuse deviceshaving upper and lower fuse terminals, the upper terminals of saiddevices being connected together, a circuit terminal, one of said fusedevices having its lower fuse terminal connected to said circuitterminal and having a circult reclosing terminal connected to the lowerfuse terminal of a second one of said devices, and

said one device having a movable member con nected to itslower fuseterminal and adapted to be released upon the occurrence of overload tobreak the connection between its .upper and lower fuse terminals and tomake connection between its lower fuse terminal and said circuitreclosing' terminal.

5. In combination, a pair of line conductor terminals, a plurality offuses adapted to be connected one at a time between said line conductorterminals, a plurality of neclosing switches for successively switchingsaid fuses into connection with said line conductor terminals, eachswitch comprising a member movable with a translatory motion andretained in position by a fuse, and released by the melting of thecorresponding fuse to permit the movable member to close the switch toconnect the next fuse between the line conductor terminals, said fuseshaving stationary housings completely enclosing said fuses and switches.

6. In combination, a pair of line conductor terminals, a plurality offuses adapted to be connected one at a time between said line conductorterminals, a plurality of reclosing switches for successively switchingsaid fuses into connec tion with said line conductor terminals, eachswitch comprising a movable member retained in position by a fuse, andreleased by the melting of the corresponding fuse to permit the movablemember to close the switch to connect the next fuse between the lineconductor terminals, each fuse and its corresponding reclosing switchbeing disposed within a. unitary housing.

'7. In' combination, a pair of line conductor terminals, a plurality offuses adapted to be conswitch comprising a movable member retained inposition by a fuse, and released by the melting of the correspondingfuse to permit the movable member to close the switch to connect thenext fuse between-said line conductor terminals, and a tubular housingfor enclosing each switch and its corresponding reclosing switch, saidtubular housing having external terminals for the fuse and the switch.

8. In combination, a pair of line conductor terminals, a plurality ofunits comprising a plurality offuses adapted to be connected one at atime between said line conductors, a plurality of reclosing switches forsuccessively switching said fuses into connection with said lineconductor 9. In combination, a pair of line conductor terminals, aplurality of fuses adapted to be connected one at a time between saidline conductor terminals, a plurality of switches for reclos ing saidfuses into connection with said line conductor terminals, each switchcomprising -a mov- 15 able member retained in position by a fuse, andreleased by the melting of the corresponding fuse to permit the movablemember to close the switch to connect the next fuse between saidterminals,

and 'a timing device controlling the rate of movement of said member. I

10. In a device of the class described, a housing having externalterminals, a fuse and a switch in said housing connected to saidterminals, an

arc extinguishing liquid in said housing disposed to assist inextinguishing the are formed on blowing of said fuse and to cover thecontact members of said switch, and an operating member for the switchheld against actuation by the fuse.

11. In combination, a housing having an incoming line terminal, a loadterminal and a reclosing terminal, a fuse in said housing connectedbetween the incoming line terminal and the loadterminal,aswitchinsaidhousingconnectedbetween the load terminal and thereclosing terminal, and an arc extinguishing liquid in said housingdisposed to assist in extinguishing the are formed on blowing of saidfuse and to cover the contact members of said switch, said switch beingclosable only upon melting of the fuse, said housing protecting the fuseand switch from adverse external influences. v

12. In combination, a power fuse. a power switch held open by the fuse,a housing for the fuse and switch to exclude adverse outside influencesand an arc extinguishing liquid in said housing disposed to assist inthe arc formed on blowing of said fuse and to cover the contact membersof said switch.

13. In combination, a power fuse, a power switchheldopenbythef'usegahousingfoi-the fuse and switch to excludeadverse-outsideinfluenceaanarcerflnsuishingliquidinsaidhousingdisposedtoamistin the areExtinguishing formedonblowingofsaidfuseandtocoverthe contact membersofsaid switch, an external connectionforoneendofthefuse,acommonexternalconnection foe the other end ofthe fuse and one element oftheswitchandanezternal 14.Inadeviceoftheclassdescribed,aplurality ofstationary fine housings havirm' fines.circuittenninalsbetweenwhiehthef'i'nuareto.beconnectedoneatatime,andaswltchineach of said housings having aswitchmember movable with a translatory motion and controlled by the'fusethereinforswitchingthefusessuceesslvely terminals.

15.Inafuseandswitchunit,ahomingcomintermediateferruleiolningsaidlleeves,enilierthesleeves,afuseterminalconnected to one end ferrule, a switch contactconnectedtotheotherendterminal, and a plunger electrically connected to said interanewmediateferruleandhavingafuseterminalat one end and a switchcontact atthe'other end, and a fuse connected between the fuse terminals andholding the plunger in position to maintain the switch contactsseparated.

l6.Inafuseandswitchunit,ahousingcom prising a pairof aligned sleeves ofinsulation, an intermediate ferrule joining said sleeves, end ferruleson the outer ends of the sleeves, a fuse terminal connected to one endferrule, a switch contact connected to the other end terminal, and aplunger electrically connected to said intermediate ferrule and havingafuse terminal at one end and a switch contact at the other end, a fuseconnected between the fuse terminals and holding the plunger in positionto maintain the switch contacts separated, a dashpot comprising astationary cylinder and a cooperating piston controlling the motion ofthe plunger.

17. In a combined fuse and switch unit, a housing, a fuse in one end ofthe housing, a switch disposed at. the other end of the housing, theclosing of the switch being prevented by thefuse, and means for delayingthe closing of the switch when the fuse is melted. I

18. In a combined fuse and switch unit, a housing, a fuse in one endofthe housing, a switch disposed at the other end of the housing, theclosing of the switch being prevented by the fuse, a dashpot fordelaying the closing of the switch when the fuse melts, said housingbeing substantially filled with liquid, said dashpot 0ccupyingsubstantially the full bore of the housing, said dashpot having apassageway therethrough to permit the passage of gas bubbles, and avalve for closing the passageway when the dashDOt is actuated.

19. In a device of the class described, a tubular housing carryingexternal terminals and having a bore, a fuse in one'end of the bore ofthehousing. aswitchintheother end ofthebore-ofthe housing, a movablemember for closing the switch,saidmemberbeingrestrainedbythefuse,apartofsaidboreprovidingadashpotcylinder andadashpotmstoncarriedby-thememberand' being adapted to cooperate with thecylinder throughoutapartofthetravelofsaidmember.

20. Inadeviceofthecl'assdescribed,atubular housing having a longitudinalbore. means at the ends of the housing forming external terminalsandanintermediateexternalterminahaplunger' insaidbore,saidplungerhavingafuse terminal electrically connected to saidintermediate ter-:minal,afuseintheendof-thehousingconnectedbetweensaidfuseterminalandtheadlacentendterminaLacoilspringsm'roundingtheplungerandbeingnormallyunderstremtotensionthefuse,aswitchintheboreremotefromthefuse,saidswitchhavingaotationasyconconnection for the other elementoftheswitch. 0

tact connectedto theadlacent end terminal, and a contact movable by theplunger, said movable contact being electrically connected to theintermediate terminal.

21'. Inadeviceoftheclassdescrlbedatubnlar housing having a longitudinalbore, means attbe endsofthehousingformingexternalterminalsandanintermediateexternalterminaha'plunger ,insaid bore,saidplungerhavlngafuseterminal-electricallyconnectedtosaidintermediatetefprisingapairofalignedlleevesofhuulatimanminaLafusei'ntheendofthehousingconnscted betweensaidfuseterminal-andth'eadjaccntsnd terminal, a 'coil spring surroundingthe plunger and being normally under stress to tension thefuse.aswitchinthebore remotefrom the fuse. saidswitch having astationary contact conneck able by the plunger, said movable contactbeing electrically connected to the intermediate terminal, and a timingdevice for retarding the motion of the plunger during a part of itstravel.

22. In a device ,of. the class described, a tubular housing having-;alongitudinal bore, means at the ends of the housing forming externalterminals and an intermediate external terminal, a plunger in said bore,said plunger having a fuse terminal electrically connected to saidintermediate terminal, a fuse in the end of the housin connected betweensaid fuse terminal and the adjacent end terminal, a coil springsurrounding the plunger and being normally under stress to tension thefuse, a switch in the bore remote .from the. fuse, said switch having astationary contact connected to the adjacent end terminal, a contactmovable by the plunger, said movable contact being electricallyconnected to the intermediate terminal, and a dashpot having a cylinderand a piston which is actuated by said plunger.

23.1n a device of the class described, a tubular housing having alongitudinal bore, means at the ends of the housing forming externalterminals and an intermediate external terminal,

' a plunger in said bore, said plunger having a fuse tenminalelectrically connected to said intermediate terminal, a fuse in the endof the housing connected between said fuse terminal and the adjacent endterminal, a coil spring surrounding the plunger and being normally understress to.

tension the fuse, a switch in the bore remote from the fuse, said switchhaving a stationary contact connected to the adjacent end terminal,

a contact movable by the plunger, said movable contact beingelectrically connected to the intermediate terminal, a 'dashpot having acylinder and a piston which is actuated by said plunger, and a bypassvalve for the dashpot closed by motion of the plunger.

24. In a device of the class described, a tubular housing having arelatively stationary switch contact at one end, a movable switchcontact, a plunger in said housing for operating said movable switchcontact to-ccoperate with said first named switch contact, means'formoving said plunger to close the switch, and a dashpot disposed withinthe bore of the tubular housing for retarding the motion of the plungeruntil a period of time has expired, whereupon the plunger is relieved ofthe retarding en'ect of the dashpot and said switch is closed.

25. In a device of the class described, a tubular housing having arelatively stationary switch contact at one end, a movable switchcontact, a plunger in said housing for operating said movable switchcontact to cooperate with said first named switch contact, means formoving ,said plunger to close the switch, and a dashpot disposed withinthe bore of the tubular housing for retarding the motion of the plungeruntil a period of time has expired whereupon the plunger is relieved ofthe retarding effect of the dashpot and said switch is closed, saiddashpot comprising a movable member cooperating with the walls of thebore.

26. In afdevice of the class described, a tubular housing comprising apair of sleeves held in coaxiaijalignment, an intermediate ferrule forhnidififgj ,s aidsleeves in' alignment, one sleeve comprising anexpulsion tube, a plunger extending through the ferrule and beingdisposed partly within the expulsion tube, a spring in the other sleevefor moving the plunger in a direction away from the expulsion tube, afuse in the expulsion tube preventing movement of the plunger, :1.switch in said other sleeve controlled by said plunger.

2'7. In a device of the class described, a tubular housing comprising apair of sleeves held in coaxial alignment, an intermediate ferrule forholding said sleeves I in alignment, one sleeve comprising a fuse tube,a plunger extending through the ferrule and being disposed partly withinthe fuse tube, a spring in the other sleeve for moving the plunger in adirection away from the fuse tube, a fuse in the'fuse tube preventingmovement of the plunger, a switch in said other sleeve controlled bysaid plunger, said fuse tube being releasable from the ferrule to permitrenewal of the fuse, said fuse having a flexible lead to permit theplunger to be moved to open the switch when the fuse is renewed.

28. In a device of the class described, a tubular housing comprising apair of sleeves held in coaxial alignment, an intermediate ferrule forholding said sleeves in alignment, one sleeve comprising a fuse tube, aplunger extending through the ferrule and being disposed partly ferruleconstituting internally a dashpot cyllnder, a dashpot piston in saidcylinder, said piston having a by-pass for gas, a valve for closin saidby-pass, means normally holding said valve in open position, a springanchor secured in terna'lly to said ferrule, a plunger extending throughthe spring anchor and piston, a spring connecting said plunger andspring anchor, a fuse holding the plunger against movement by thespring, and a switch adapted to be actuated by the plunger, said dashpotpiston retarding the intermediate part of the motion of the plunger.

30. In a device of the class described, a pair of axially alignedsleeves, an intermediate ferrule holding the sleeves together inalignment,

said ferrule constituting internally a dashpot cylinder, a dashpotpiston in said cylinder, said piston having'a by-pass for gas, a valvefor closing said by-pass, means normally holding said valve in openposition, a spring anchor secured internally to said ferrule, aplungerextending through the spring anchor and piston, a spring connecting saidplunger and spring anchor, a fuse holding the plunger against movementby the spring, and a switch adapted to be actuated by the plunger, saiddashpot piston retarding the intermediate part of the motion of theplunger, said plunger'having .an enlargement adapted to close said valveand serving as -.a guide within the spring anchor.

31. In combination, a housing having a movable plunger, a stationaryswitch contact carried in the housing, a cooperating movable" switchcontact operated by the plunger, a dashpot in the housing for retardinga part of the motion of the plunger, and a body of liquid covering saidswitch contacts when they are about to close and serving as a workingmedium for the dashpot.

32. In combination, a housing having-a movable plunger, a stationaryswitch contact carried in the housing, a cooperating movable switch,contact operated by the plunger, a dashpot in the housing for retardinga part of the motion of the plunger, and a body of liquid covering saidswitch contacts when they are about to close and serving as a workingmedium for the dashpot, a fuse having separable terminals actuated bysaid plunger, said liquid serving as an arc extinguishing medium for thearc resulting from the melt-- posite the'fuse a cylindrical contactmember, a

cooperating contact socket within the housing and connected to the otherend terminal, said socket comprising a circular guide of insulation,

a plurality of contact fingers adapted to embrace the cylindricalcontact member of the plunger, and a garter'spring surrounding thecontact fingers and holding the same under stress against the guidingring. I

34. In a circuit controlling device, .the combination of a first fuse, asecond fuse, switching means controlled by melting of the first fuse totransfer the circuit from the .first fuse to the second fuse, and timingmeans for controlling the operation of said switching means comprising apair of hermetically sealed liquid containing chambers having a flowrestricting passage connecting them, and movable means for-forcing theliquid from one chamber into the other controlling said switching means.

35. A fuse device for use in connection with a switch, a spring forbiasing the contact members repeating fuse mechanism or the likecomprising, I

36. In combination, a tubular housing having an incoming line terminalmember. a load terminal member and a reciodng terminal member, a switchmember electrically connected to said land terminal member and biasedfor movement axially of said tubular housing into contact engagementwith said reciosing terminal member, and fusible means electricallyinterconnecting said line terminal member and said s'witchmember andmechanically restraining the 'latter, said fusible means on blowingopening the circuit between said line and load terminal members andreleasing said switch member to close a circuit between said load andreclosing terminal mem-. bers The combination with a pair of renewablefuse devices and a transfer switch for shifting a drcuit from one fusedevice to the other when delaying the transfer of said circuit to saidother.

.fuse device. comprising a chamber having a fixed wall at one end and arelatively movable wall at the other end, one of said walls having arestricted aperture associated therewith to permit fiuid to fiowtherethrough, the delay action of said timing device being provided bymovement of said movable wall toward said fixed wall as controlled bythe flow of fluid out of'said chamber through said restricted aperture,and check valve means I operating to permit free movement of saidmovable wall away from said fixed wall.

38. A hydraulic escapement device fordeterminingthe time between theblowing of one fuse of a reclosing fuse device and the closing of atransfer switch to reestablish the circuit through the next fusecomprising, in combination, a cylinder closed at one end, a pistonslidably mounted in said cylinder, a check valve in said piston.disposed to be closed when it is moved towardsaid closed end and to beopened when moved in the opposite direction,- an opening extendingtransversely through said piston, and a needle valve disposed tocooperate with said opening.

39. In reclosing fuse apparatus, inwcombination, a timing device fordetermining the interval between the blowing of one fuse device and theclosing of a transfer switch to reestablish the circuit through the nextfuse device, and a lost motion member cooperating with said timingdevice to retard the closing of said switch after one fuse device blows,said lost motion member being arranged and adapted to prevent the timingdevice from offering resistance to the restoration of the blown fusedevice to its normal operating posi tio 40. The combination, with a pairof fuse de-- vice and a transfer switch for shifting a circuit from onefuse device to the other when the one fuse device blows, of a fusemember operating on blowing of a fusible element of said one fusedevicefor initiating the operation of said transfer of said switch intocontact engagement, and

means arranged and adapted to prevent said contact members fromrebounding on engagement thereof.

. 41. In combination, a pair of fuse devices and a transfer switcharranged and adapted to shift a circuit from one fuse device to theother fuse device on blowing of the fusible element of said one fusedevice, said transfer switch including a movable switch member actuatedon blowing of said fusible element, a stationary switch member disposedto be engaged by said movable switch member, .a plurality of contactfingers on one of said switch members for effecting contact engagementwith said other switch member, and resilient means bias'ng said fingersinto said contact engagement. 7

42. In combination, a pair of fuse devices andatransferswitcharrangedandadaptedtoshifta circuit from one fuse devicetothe other fuse deviceon blowing of the fusibleelement of said one fusedevice, said transfer switch including a movable switch member actuatedon blowing of said fusible eiunent, a stationary. switch memberdistposed to be engaged by said movableswitch memthe one device blows,of a timing device for movement of said fingers under the infiuence of

